fix Dockerfile.gpu.devel

tools/Dockerfile.gpu.devel

@@ -4,7 +4,7 @@ RUN yum -y install wget >/dev/null \
     && yum -y install git openssl-devel curl-devel bzip2-devel python-devel \
     && yum -y install libSM-1.2.2-2.el7.x86_64 --setopt=protected_multilib=false \
     && yum -y install libXrender-0.9.10-1.el7.x86_64 --setopt=protected_multilib=false \
-    && yum -y install libXext-1.3.3-3.el7.x86_64 --setopt=protected_multilib=false \
+    && yum -y install libXext-1.3.3-3.el7.x86_64 --setopt=protected_multilib=false
 
 RUN wget https://cmake.org/files/v3.2/cmake-3.2.0-Linux-x86_64.tar.gz >/dev/null \
     && tar xzf cmake-3.2.0-Linux-x86_64.tar.gz \